[pmoyjr]

I purchased a new RM-200 Mk II about 3 weeks ago on AudiogoN.  I speculate  it was one of the samples Roger offered at a discount to Audio Circle members.  Before hooking it up to my preamp and speakers, I plugged it in and turned on the capacitor forming switch.  It immediately began humming and continues to hum as long as it is turned on--whether playing music or not.  Has anyone else experienced this humming phenomenon?  It now is a distraction because I moved the amp to a position between my speakers to give it space for heat dissipation.  It initially sat in an audio rack in a corner outside the speakers.

[rbwalt]

try keeping your interconnects away from the transformers if you have not done so. roger's amps are usually dead quiet. e-mail roger on it and he will solve it for you. by the way can you hear it hum from your seating or do you have to get right up to it to hear it hum? i had a rm9mk2 that had some hum now my rm9se does not and is dead quiet.

good luck. when you do get it solved you are going to love the amp. do not give up on it or let it sour you on MR products.

r.

[eeramos]

I also recently purchased a RM-200 MKII. Mine direct from RAM Labs. No hum - dead quiet. Check with Roger.

[jamesgarvin]

Do you mean a hum from the speakers or the amp itself? Mine experienced a low level hum when new, but stopped some time later. I can't pinpont when it stopped, because I could never hear it unless I sat next to the amp. Now it is dead quiet.

[Ericus Rex]

If it hums before connecting any cabling I would think it's the transformer humming.  Sounds unusual for Music Reference.  Give Roger a call or PM him here.  Be sure to include "question from Audiocircle member" in the title of the PM so he'll see it right away.

[pmoyjr]

The humming occurred before any cables were connected and before the "Play" switch was actuated to drive the tubes.  Thanks to everyone for your feedback.  I will email Roger with the details.

[Scottdazzle]

Be sure to use shielded interconnect cables and route them away from the transformer.

[Roger A. Modjeski]

Sounds like direct transformer noise. I have sent a message to the owner. It is a very difficult matter to make silent transformers and I take great effort in the process. I have found in some cases that tightening the four screws that hold the laminations together is helpful. Although we tighten them as much as one can, over time as the varnish continues to dry and shrink there can become some looseness in the laminations.